opts.js

/* litejs.com/MIT-LICENSE.txt */

exports.opts = opts

function opts(defaults, argv) {
	var expect, key, val
	, i = -1
	, short = {}
	, hasOwn = short.hasOwnProperty
	, out = {_: [], _valid: [], _unknown: []}
	, isElectronBinary = process.versions.electron && !process.defaultApp

	if (!argv) argv = process.argv.slice(isElectronBinary ? 1 : 2)

	for (; (val = argv[++i]); ) if (val[0] !== "-") {
		for (key in defaults) if (isObj(defaults[key])) {
			expect = key.split("_")
			if (expect[0] === val || expect[1] === val) {
				out._cmd = expect[0]
				argv.splice(i, 1)
				defaults = Object.assign({}, defaults, defaults[key])
				break
			}
		}
		break
	}

	for (key in defaults) if (!isObj(defaults[key])) {
		val = key.split("_")
		out[val[0]] = defaults[key]
		if (val[1]) short[val[1]] = val[0]
	}

	for (i = 0; i < argv.length; i++) {
		val = argv[i].split(/=|--(no-)?|(^-)/)
		if (val[0] === "" && argv[i][0] !== "=") {
			key = val[2] && short[val[3][0]]
			if (key) {
				expect = val[3].slice(1)
				if (typeof out[key] === "boolean" && expect) {
					argv.splice(i--, 1, "--" + key, "-" + expect)
					continue
				}
				val[3] = val[6] = key
				argv[i] = "--" + key + "=" + (expect || argv.splice(i + 1, 1))
			}
			key = val[3].replace(/\-([a-z])/g, camelFn)
			if (key === "") {
				argv.push.apply(out._, argv.slice(i + 1))
				break
			}
			if (hasOwn.call(out, key)) {
				expect = Array.isArray(out[key]) ? "array" : typeof out[key]
				val = val[1] ? 0 : typeof val[6] === "string" && argv[i].slice(val[3].length + 3)
				out[key] = (
					expect === "boolean" ? val !== 0 && (val === false || val === "true" || val !== "false" && castError()) :
					expect === "array" ? (out[key] === defaults[key] ? [] : out[key]).concat(val ? val.split(",") : []) :
					expect === "string" ? val || "" :
					expect === "number" && val !== false ? +val :
					castError()
				)
				out._valid.push(argv[i])
			} else {
				out._unknown.push(argv[i])
			}
		} else {
			out._.push(argv[i])
		}
	}
	return out

	function camelFn(_, chr) {
		return chr.toUpperCase()
	}
	function castError() {
		throw "Invalid value for option '" + key + "' - expected " + expect
	}
	function isObj(obj) {
		return obj && obj.constructor === Object
	}
}